St. Petersburg - Top-seeded Fabio Fognini has retired with a right foot injury while trailing Michal Przysiezny of Poland 6-3, 5-3 on Thursday in the second round of the St. Petersburg Open.
The 17th-ranked Italian, who was looking for his third title, struggled with his right foot throughout the match and never threatened his opponent with a break.
Also, fourth-seeded Dmitry Tursunov advanced to the quarter-finals by beating Russian qualifier Konstantin Kravchuk 6-3, 6-0.
Tursunov will next face Joao Sousa of Portugal, who rallied to beat Sergiy Stakhovsky of Ukraine 3-6, 6-4, 6-0.
Seventh-seeded Lukas Rosol defeated Russian wild card Karen Khachanov 6-4, 6-4.
Results from the fourth day of the ATP St Petersburg Open on Thursday (x denotes seeding):
Michal Przysiezny (POL) bt Fabio Fognini (ITA x1) 6-3, 5-3 - retired
Lukas Rosol (CZE x7) bt Karen Khachanov (RUS) 6-4, 6-4
Roberto Bautista (ESP) bt Evgeny Donskoy (RUS) 2-6, 6-1, 7-6 (7/5)
Ernests Gulbis (LAT x6) bt Jurgen Zopp (EST) 6-3, 1-6, 6-3
Joao Sousa (POR) bt Sergiy Stakhovsky (UKR) 3-6, 6-4, 6-0
Dmitry Tursunov (RUS x4) bt Konstantin Kravchuk (RUS) 6-3, 6-0